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He Y.,China Academy of Engineering Physics | Luo J.,China Academy of Engineering Physics | Li K.,China Academy of Engineering Physics | Luo B.,China Academy of Engineering Physics | And 5 more authors.
RSC Advances | Year: 2016

Beryllium carbide (Be2C) films were first deposited on optical quartz substrates by DC reactive magnetron sputtering on a beryllium target with variable CH4-Ar ratios. The influence of CH4-Ar ratios on the composition, microstructure and optical properties were investigated by X-ray photoelectron spectroscopy, X-ray diffraction, high-resolution transmission electron microscope, atomic force microscopy, scanning electron microscope and UV-vis spectrum. The main component in the films prepared at lower CH4-Ar ratios (<5%) was Be2C, while hydrocarbon (CH) films were formed at higher CH4-Ar ratios (>15%). The films exhibited a nanocomposite structure consisting of Be2C nanocrystals (3 to 5 nm in size) embedded in amorphous hydrocarbon matrices. A smooth surface and columnar structure on the cross-sectional view were revealed. Besides, the depositing rates reached ∼125 nm h-1, which were significantly higher than that of RF reactive magnetron sputtering. High transparency (>50%) of the Be2C films in the visible region as well as an even higher transparency (>80%) in the near-infrared region were demonstrated. Finally, the dispersion of the optical constants of Be2C films is presented, and the optical bandgaps were evaluated to be ∼2 eV. The good properties of Be2C films prepared by DC reactive magnetron sputtering showed that this material could be a potential candidate for application to inertial confinement fusion targets. © The Royal Society of Chemistry 2016.


Gao N.,Science and Technology on Plasma Physics Laboratory | Gao N.,China Academy of Engineering Physics | Bo Y.,China Academy of Engineering Physics | Yi Y.,China Academy of Engineering Physics | And 5 more authors.
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2015

The communication demonstrates an effective and simple method for mass production of metallic micro/nanowire arrays. The three dimensional geometric parameters of the metallic array can be tuned over a large range, from micron to nano-scale. Metallic micro/nanowire arrays with largely tunable diameter and spacing can be used to studying the interaction of intense femtosecond laser pulses with matter. © 2015, National Institute of Optoelectronics. All rights reserved.


Luo B.C.,China Academy of Engineering Physics | Luo B.C.,Science and Technology on Plasma Physics Laboratory | Li K.,China Academy of Engineering Physics | Tan X.L.,China Academy of Engineering Physics | And 6 more authors.
Journal of Alloys and Compounds | Year: 2014

The Be coating grown on K9 substrate are fabricated at different annealing temperatures by dc magnetron sputtering, and they are composed of α-Be phase with hcp structure from XRD analysis. As the in situ annealing temperatures increase from 60 °C to 410°C, the coating surfaces show the transition from fibrous grains dominated by surface diffusion to diamond-like grains, and then to recrystallized grains dominated by bulk diffusion. For the coating cross-section morphologies, they are always characterized by the coarsening columnar grains with distinct boundaries. Both surface roughness and grain size increase with annealing temperatures, and obey the modified Anelli model. Moreover, the constitutive relationship of Be coating was explored. The residual stress is related closely to the microstructures and annealing temperatures, not only displays the tensile stress but also compressive stress. The compression-tension transition temperature occurs near 250°C (0.34T m), which is just recrystallization transition temperature. The film electrical resistivity values decrease gradually with the increase of grain size due to the reduction of grain boundary. © 2014 Elsevier B.V.


Yang B.,China Academy of Engineering Physics | Niu G.,China Academy of Engineering Physics | Niu G.,Science and Technology on Plasma Physics Laboratory | Zhou X.-W.,China Academy of Engineering Physics | And 6 more authors.
Polymer Engineering and Science | Year: 2015

Well-ordered, globally oriented composite fibers with micro/nanowire arrays of polystyrene (PS) fibers embedded in polyethylene (PE) were prepared by an iterative melt co-drawing and the bundling technique. With section-cutting of the PE/PS fiber and the dissolution of inner PS, porous PE fibers were obtained. Optical microscopy and scanning electron microscopy (SEM) showed that the distribution of pores were regular hexagonal, the diameters of the pores after the third drawing step were about 175 nm, and the spacings of pores were 1-2 micron. There was good agreement between calculated and experimental values for the pore diameters and spacings. The obtained porous template was used to prepare Cu nanowires by electrochemical deposition. SEM in combination with the energy dispersive X-ray analysis (EDX) indicated that Cu nanowires were successfully deposited in the pores of the template. Potential applications of this simple and inexpensive fabrication technology were discussed for preparing micro/nanowire arrays with highly controllable geometric parameters. © 2014 Society of Plastics Engineers.


Mu J.,China Academy of Engineering Physics | Mu J.,Science and Technology on Plasma Physics Laboratory | Jing F.,China Academy of Engineering Physics | Jing F.,Science and Technology on Plasma Physics Laboratory | And 9 more authors.
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2014

Stochastic parallel gradient descent (SPGD) is an effective way to achieve multi-channel phase-locked laser beams for coherent beam combination (CBC). In this paper, the influence of piston error and tilt error on CBC is primarily presented. Then, an arrangement model of 2×2 laser beams is built. With this proposed model, SPGD is tested and verified. Key parameters, the gain coefficient and the disturbance amplitude, impacts on the error control performance of the algorithm, are analyzed and optimized. The surveys show that it is necessary to control piston error and tilt error for CBC. When SPGD is used to correct the above errors, the convergence speed of the algorithm is improved with the increase of the gain coefficient and the disturbance amplitude, however, the accuracy of SPGD is reduced and the system is vibrated. In order to improve CBC, the adaptive gain coefficient is studied. Compared with the fixed gain coefficient, the adaptive gain coefficient is able to make a good balance between the convergence speed and the accuracy of the algorithm, which indicates that the adaptive gain coefficient is an effective optimization way. These results in this paper provide a theoretical reference for CBC using SPGD in a large short-pulse laser facility.

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